(a) Field of the Invention
An exemplary embodiment of the present invention relates to an active damper and a driving method thereof.
(b) Description of the Related Art
An AC input passed through a dimmer is rectified through a rectification circuit and then supplied to a power supply. The AC input rectified through the rectification circuit becomes an input voltage and an input current of the power supply.
The AC input passed through the dimmer is cut according to a dimming angle. That is, a portion corresponding to the dimming angle is passed through the dimmer during one cycle of a sinewave AC input.
When the AC input passed through the dimmer is rectified, a portion where the input voltage and the input current are rapidly increased is generated and spike of the input voltage or ringing of the input current occurs in the portion. A negative current due to the ringing of the input current may cause a problem of turning off the dimmer.
A damper is an element provided between the rectification circuit and the power supply to prevent the spike of the input voltage and the ringing of the input current. In general, the damper is realized as a resistor.
In this case, the spike and the ringing cannot be effectively prevented with the damper uses low resistance. Accordingly, power consumption and temperature problems occur due to the damper resistance.
FIG. 1 shows an input voltage and an input current when resistance of the damper of 25Ω.
FIG. 2 shows an input voltage and an input current when resistance of the damper is 200Ω.
As shown in FIG. 1, when the resistance is 25Ω, spike and ringing are generated in the input voltage and the input current, respectively.
However, as shown in FIG. 2, when the resistance is 200Ω, spike and ringing are not generated in the input voltage and the input current in a circle area marked by the dotted line.
However, the power consumption and temperature increase still remain as problems.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.